Did you pay for ProSeries Basic and are now using ProSeries Professional?
If so, youd have to PPR for returns prepared in Professional.
If you paid for unlimited in Professional, and are suddenly being prompted to PPR, try to update your licensing.
Tools > License Products
I am having the same issue. I bought the Basic unlimited 1040s and why I tried to print the 1040 I'm being asked to pay. I should not have to pay anything. This is the first return for 2020.
I did as suggested and updated but that did not fix the issue.